In the state of the art, the rolls of reworking mechanisms that are located downstream from a chopping drum in a forage harvester can be positioned mechanically in a definite spacing (EP 2 098 110 A2). The problem of an optimal adjustment of the spacing between the rolls of the reworking mechanism arises here. If the spacing is small, a secure striking of the grains contained in the harvested crop is indeed assured, but (in relation to rolls arranged at a greater distance) the feed rate is reduced and the energy requirement for driving the reworking mechanism is increased. These shortcomings are avoided by increasing the distance, but in the case of a wet crop the grains are not struck sufficiently securely due to their greater elasticity as compared with a dry crop. Then the animals fed with the crop material cannot digest it completely.
DE 100 30 505 A1, which is considered type-forming, describes a reworking arrangement having two rolls, the spacing or compressive force of which is automatically adjusted as a function of a parameter of the harvested crop, in particular, the moisture content.
In chopping the crop a certain proportion of the grains in the crop is struck by the knives of the chopping drum. This proportion, which is larger the shorter the chopping length, is not taken into account in the automatic adjustment of the distance between the rolls of the reworking mechanism according to DE 100 30 505 A1.
The problem underlying the invention is thus considered to be achieving a reliable striking of the grains contained in the crop along with as low as possible input power requirement of the reworking mechanism.